Question: 1. An equilateral triangle is standing vertically with a vertex above the xy-plane and its two other vertices at (7, 0, 0) and (9, 0, 0). What is its highest point?
2. If f(x, y) is a function of two variables defined for all x and y, then f(10, y) is a function of one variable.
3. The volume V of a box of height h and square base of side length s is a function of h and s.